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Monday, March 24, 2014

Kirtland’s Warbler

by Frank Boles

On March 17, William Rapai, author of The Kirtland’s Warbler: The Story of a Bird’s Fight Against Extinction and the People Who Saved It, presented a moving tribute to the men and women who saved Kirtland's Warbler from extinction. His book adds the story of a community that embraced the project despite tragedy.

Kirtland’s Warbler is a Michigan bird, and a persnickety one. It nests in a relatively small, twelve county area of north-central Michigan among young jack pines. Not only is the bird persnickety, so too is the tree under which it nests (Kirtland’s Warblers build their nests on the ground). Jack pine seed cones only open in the presence of intense heat – usually a forest fire. Fire literally clears the field of competing species, allowing jack pines to seed and grow.

In 1851, Charles Pease shot and donated to the Smithsonian Institution the first bird identified as a Kirtland’s Warbler. But for the rest of the nineteenth century the bird was largely a mystery. It wintered in the Bahamas, but where it nested was unknown. In 1903, Norman Wood, a taxidermist employed by the University of Michigan’s Museum of Natural History, discovered the bird’s nesting ground among northern Michigan’s jack pine. Perhaps “discovered” was a bit of an overstatement. Wood may have published the data, but people in the area had long referred to the Kirtland’s Warbler as “the jack pine bird.”

Whoever first found the bird’s nesting sites, Kirtland’s Warbler was considered a charming little creature with a lovely song. But the charming little bird was about to become endangered. Harold Mayfield, a gifted amateur birder, surveys, organized the first decennial population survey of the species in 1951 and realized the bird was in deep trouble. Josselyn Van Tyne from the University of Michigan’s Museum of Natural History specialized in the Kirtland’s Warbler and worked closely with Mayfield. Van Tyne planned to write the definitive book on the bird, but died before he could complete the project. Mayfield, inherited Van Tyne’s notes, and combined with his own knowledge completed the book in 1960, and offered an explanation of why Kirtland’s Warbler was in decline.

The reason for the problem was human induced changes in the bird’s nesting habitat. The bird almost always nested among stands of young jack pine. Young jack pine, however, came about because of fire, and the state of Michigan’s forest management plans basically sought to eliminate forest fires. No fires, no young jack pine. No young jack pine, no Kirtland’s Warblers.

But as it turned out there was an even more difficult problem -- an invasive species accidentally introduced into the region was also a threat. The Brown-headed Cowbird was a resident of the Great Plains, which found its way into Michigan when the state’s lumber industry all but deforested Michigan, making it look, from a Cowbird’s perspective, like the treeless Great Plains. Cowbirds originally lived by following the bison – eating seeds and grain the bison disturbed as well as the insects which swarmed around the great animals. When the bison was all but exterminated, Cowbirds found a new large animal to live with, domestic cattle.

This migratory lifestyle of bison made nesting difficult a problem for which Cowbirds developed a unique, if unsavory solution -- "brood parasitism.” Less scientifically, a Cowbird can lay up to thirty eggs in a season. It does this a few at a time, dropping one or more eggs into another bird’s nest, “disposing” of an equal number of the original bird’s eggs, and moving on – leaving the hatching and nursing of young Cowbirds to the unsuspecting mother bird.

Lawrence Walkinshaw was a dentist from Battle Creek whose first love was ornithology. Walkinshaw was the first to notice the devastating impact the Cowbird was having on the Kirtland’s Warbler. In a study he did between 1966 and 1971, he determined that 69% of the Warblers’ nests included Cowbird eggs. Worse, when a Cowbird hatched in a Warbler nest, it was usually the sole fledging to survive into adulthood. Walkinshaw’s work was not easy. The Warbler was particularly difficult to track to a nest, and fellow researchers marveled as Walkinshaw’s ability to sit motionless and watch a Warbler’s flight, even when he was being bitten by insects so frequently that blood would run down his face. Walkinshaw, however, was a man driven.

The 1971 decennial census of Kirtland’s Warbler made clear that a crisis was at hand. The bird’s population had declined to about 200 nesting pairs. Additional studies of parasitism revealed that Cowbirds had so infested Kirtland’s Warbler nests that the Warblers were producing only .81 birds of their own species per nest.

To address the problem, Central Michigan University’s Nicholas Cuthbert had spent the previous decade exploring how to limit Cowbirds from the Warbler’s breeding ground, eventually perfecting a Cowbird trap. Cowbirds are social by nature. If one is placed in a trap that also includes a generous supply of food and water, others will soon walk into the trap to enjoy both the company and the meal. Trapping worked. Areas in which traps were set in sufficient number saw the average brood of warbler’s per nest increase from .81 to 2.84. But a plan was needed.

In 1971, the Kirtland’s Warbler Advisory Committee was formed, with all of the important actors sitting at the table. They agreed on a comprehensive plan. Key to the plan was agreement by the U.S. Fish and Wildlife Service to undertake a bird control program to limit the number of Cowbirds and an agreement that both the state of Michigan and the Fish and Wildlife Service would accelerate plans to obtain and set aside stands of young jack pine.

The Committee created both a vision and a culture of cooperation that fit perfectly into the federal Endangered Species Act, enacted in 1973. But the road forward was still uncertain. Efforts to raise Kirtland’s Warblers in captivity failed. And despite many small parcels of land with young jack pine being set aside, the birds remained slow to repopulate. The problem, it turned out, was fire, or more properly the lack of it.

On May 5, 1980, a controlled burn near Mio, Michigan went wild. One Forest Service worker died in the blaze, one small community was destroyed, and the Mack Lake fire charred 40 square miles before it was brought under control and extinguished. Burton Barnes from the University of Michigan saw the possibility of salvaging something of value from this tragedy -- a path breaking study on the impact of widespread wildfire on nesting among Kirtland’s Warblers. The results made clear that large scale, eco-system management was the key to the Warbler’s survival. By 1996, nearly 70 percent of Kirtland’s Warbler nests were found in the area of the Mack Lake Fire. Kirtland’s Warblers bred most productively not in small jack pine woodlots but rather in large areas devastated by fire and holding large numbers of young jack pine. Out of tragedy and death came the knowledge to help one small bird live.

How to balance the two will be long discussed, since many in Mio and the surrounding area never forgave the Forest Service for the May 1980 fire. Some local residents also never forgave the Warbler, which was pictured in a local poster with in a red circle with a slash through it. The Forest Service itself stopped all controlled burns after the disaster until it could review and eventually rewrite its manual regarding controlled burns and retrain its personnel. As one Michigan DNR official eventually put it, “Mack Lake was a disaster in a lot of ways, but it came along at the right time.”

Lingering resentment led to a second action plan in the early 1990s; one that supplemented the plan to save the bird with one to explain why and how this was being done to the public generally and specifically to the people who had suffered through the Mack Lake fire. The need to educate the public came none too soon. In 1991, a resolution had been introduced in the Michigan House of Representatives calling for the complete re-examination of the Kirtland’s Warbler program. Although the resolution was never passed, it made clear the public anger resulting from the Mack Lake Fire remained. Saving the Warbler meant not just planning about a bird but explaining to the public why saving a bird and managing an eco-system mattered.

In the end the publicity plan worked – not so much because it was good public relations, but because it proposed a sound program that made sense for everyone involved: the wildlife professionals working to preserve the Kirtland’s Warbler as well as manage the local habitat, private property owners, and the community as a whole. In 1994, Mio held its first annual Kirtland’s Warbler Festival. It was a turning point that changed the Kirtland’s Warbler from an obscure bird benefitting from the work of a small but dedicated group of volunteers and professionals into a public embrace and celebration of the Kirtland’s Warbler and its habitat.

The story Bill Rapai shared was quite a tale.
  • A story of survival against habitat change and invasive species.
  • A story of dedicated volunteers, scientists, and public officials working together to accomplish a difficult goal.
  • A story of learning from tragedy, by both government officials and the public.
It is a story that perhaps we all can learn from – that that dedicated volunteers, scientists, public officials, and a community as a whole can work together to create change for the better.